Posted a message on 11-03 about bogging down when rpms drop back to idol. Did not get any replies, Please if anyone has had any similar issues or any ideas. I have been to the dealership 3 times and had throttle body cleaning, idol relearn, checked for air leaks. HELP!!!!!:horse:
Still having idle issues
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Hmmm
Interestin....I have a few questions that will open the doors to me why its boogin down...
When you start the engine, does it rev a bit high, above 1500 and below 2500rpm?
Off idle does it run normally or are there any abnomalities?
How many miles do you have on it?
When was the last time you changed the fuel filter?
When was the last time you changed the ignition wires and plugs?
What modifacations have you done and what was the vehicles reaction to each?
Have you tuned the engine at a dyno?
Lookin forward to your reply, and your answers...
Naf
Interestin....I have a few questions that will open the doors to me why its boogin down...
When you start the engine, does it rev a bit high, above 1500 and below 2500rpm?
Off idle does it run normally or are there any abnomalities?
How many miles do you have on it?
When was the last time you changed the fuel filter?
When was the last time you changed the ignition wires and plugs?
What modifacations have you done and what was the vehicles reaction to each?
Have you tuned the engine at a dyno?
Lookin forward to your reply, and your answers...
Naf
First off thanks for any help you can offer!!
1)I will look to see if it revs abit high, it seems to start normal with the slight fluctuation from the cam at idle.
2)Off idol it runs normal no sputtering, smooth acceleration, etc. it is just when I let off the gas to shift to neutral or downshift and the rpms drop to idol it doesnt seem to catch itself around the normal range of 700-800rpm it will drop down to 500 sometimes 400 rpm then the computer seems to compensate and kick them back up. This seems to happen mostly in the first few minutes after startup. Most common right after startup if Im backing out of parking spot or go to leave and shift to neutral at stop sign when the rpms fall back to idol the engine boggs down to low.
3)I have 27K miles
4)I have not changed the fuel filter yet but I would have thought if it was filter related I would have driveability issues also.
5)Ignition wires and plugs are original dealer says good to 100K
6)The only mod is a lingenfelter intake but it has been installed all along even previous to current issue.
7)I am planning on taking the car to be tuned by a local shop with a chevy block specialist but I wanted to make sure and fix the problem prior to doing so incase it was warranty related work, also I will be getting an exhaust probably the magnaflow so I wanted to tune after installation.
What I know for a fact is that this issue started after the battery was replaced and while disconnected I cleaned out the throttle body. The dealership has done the idol relearn and there are no codes being kicked. Of course like everything else it doesnt seem to act up as much when they have the car at the shop.
Thanks for the input
Naf thx for the input I posted an reply w/ answers to questions. Look forward to any help you can offer!!
1)I will look to see if it revs abit high, it seems to start normal with the slight fluctuation from the cam at idle.
2)Off idol it runs normal no sputtering, smooth acceleration, etc. it is just when I let off the gas to shift to neutral or downshift and the rpms drop to idol it doesnt seem to catch itself around the normal range of 700-800rpm it will drop down to 500 sometimes 400 rpm then the computer seems to compensate and kick them back up. This seems to happen mostly in the first few minutes after startup. Most common right after startup if Im backing out of parking spot or go to leave and shift to neutral at stop sign when the rpms fall back to idol the engine boggs down to low.
3)I have 27K miles
4)I have not changed the fuel filter yet but I would have thought if it was filter related I would have driveability issues also.
5)Ignition wires and plugs are original dealer says good to 100K
6)The only mod is a lingenfelter intake but it has been installed all along even previous to current issue.
7)I am planning on taking the car to be tuned by a local shop with a chevy block specialist but I wanted to make sure and fix the problem prior to doing so incase it was warranty related work, also I will be getting an exhaust probably the magnaflow so I wanted to tune after installation.
What I know for a fact is that this issue started after the battery was replaced and while disconnected I cleaned out the throttle body. The dealership has done the idol relearn and there are no codes being kicked. Of course like everything else it doesnt seem to act up as much when they have the car at the shop.
Thanks for the input
Naf thx for the input I posted an reply w/ answers to questions. Look forward to any help you can offer!!
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There's your problem.
Double and triple check your intake tract for leaks. You had to disconnect everything to get at the TB, so I suspect you may have a small air leak. If that doesn't work, try a throttle relearn:
(from the FAQ- Thanks Reed! :thumbsup
# Turn car off, wait a few seconds.
# Hold throttle to the floor and keep it there while trying to start the car. It won't start (try only once).
# Turn off ignition.
# Wait about 15 seconds.
# Start car.
If you used anything abrasive on the throttle body it can also cause extra airflow at idle by opening up the area around the throttle plate, but I doubt you did that.
Ive checked the intake several times for any air leaks and tightened and retightened all clamps. Im also thinking that if it was an air leak it would have to be after the MAF sensor to cause this issue. I also checked the intake tube for cracks or leaks and even got the dealer to warranty out a new one. The dealership did the idol relearn procedure and that has not seemed to change anything. Is there any variation to the idol learn procedure to compensate for A/C on or off, and any differences with transmission in gear or in neutral? Im starting to wonder if something is wrong with the idol control motor but it is not kicking a code. Could something be out of adjustment with the actual flapper valve that the idol control motor is controlling? Thanks for the input!!
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I blew my motor awhile back, when I could have had a simple compression test. My car would even try to stall when the air conditioner was blowing somewhat hard. I would check into the compression if it is not under warranty.
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Hmm, there are alot of issues lingering, but everything would have an effect
-If he had a leaky TB the rpm would be high not low...
-If he had a leak in the intake manifold again, RPM would be high not low
-I noticed he has a new intake kit and no tune....Has the weather changed and this started to act up?
Also i would have them check out the fuel pump pressure...When it is cold/hot it may act the same way at low rpm. If i am not mistaken it has an internal releif line, which could be causing a problem at low rpm, but once you kick it the flow follows up and there are no issues. There is a nipple on the fuel rails ant if you are at 58psi at idle you are fine, if you are lower, that would cause the issue...Being higher might also cause issues, but never experienced that to make any factual comments.
Idle is one of the ignored sections in a engine. Most people think that if it runs fine then ignore the idle...I believe if you cant keep an open soda can in the car during idle, you are doing something wrong. Idle is more important to me then top end power...
-If he had a leaky TB the rpm would be high not low...
-If he had a leak in the intake manifold again, RPM would be high not low
-I noticed he has a new intake kit and no tune....Has the weather changed and this started to act up?
Also i would have them check out the fuel pump pressure...When it is cold/hot it may act the same way at low rpm. If i am not mistaken it has an internal releif line, which could be causing a problem at low rpm, but once you kick it the flow follows up and there are no issues. There is a nipple on the fuel rails ant if you are at 58psi at idle you are fine, if you are lower, that would cause the issue...Being higher might also cause issues, but never experienced that to make any factual comments.
Idle is one of the ignored sections in a engine. Most people think that if it runs fine then ignore the idle...I believe if you cant keep an open soda can in the car during idle, you are doing something wrong. Idle is more important to me then top end power...
I'll be interested to find out the cause of your problem. My C5 has a similar problem since I had the 402 installed with a 236/240 cam. My local tuner is trying to figure it out, but we are guessing that is something to do with the cam and the tune.
Sorry I'm not any help.
Sorry I'm not any help.
I am still not clear on what the actual issue is here.
What is the car doing? I mean it seems like an idle issue, but what are the specific symptoms?
A few points I'd like to mention:
1. There is no idle learn procedure for the CTS-V.
2. The "idle control motor" is the throttle control motor, if there was an issue with the throttle body's ability to control the idle speed, codes would set and the drive by wire throttle wouldn't work, or it would run in limp mode.
3. You could have bad motor mounts transferring too much engine vibration to the body. This engine runs at a low rpm and can be really shaky because of the cam and the way the engine is designed. If the mounts are bad this can feel amplified greatly and make you think you have a problem that you don't.
4. If you still have the stock air box, install it temporarily and see if the concern goes away. If it does then it would be related to your CAI install. If it is the same you know it is a stock issue. The air boxes on some of these sometimes are sensitive to airflow issues to the MAF, I have seen lots of V's without issues with all sorts of different air intake setups though, so it shouldn't be.
Here is a list from the FSM of things to check for an unstable or incorrect idle.
Hope this Helps.
What is the car doing? I mean it seems like an idle issue, but what are the specific symptoms?
A few points I'd like to mention:
1. There is no idle learn procedure for the CTS-V.
2. The "idle control motor" is the throttle control motor, if there was an issue with the throttle body's ability to control the idle speed, codes would set and the drive by wire throttle wouldn't work, or it would run in limp mode.
3. You could have bad motor mounts transferring too much engine vibration to the body. This engine runs at a low rpm and can be really shaky because of the cam and the way the engine is designed. If the mounts are bad this can feel amplified greatly and make you think you have a problem that you don't.
4. If you still have the stock air box, install it temporarily and see if the concern goes away. If it does then it would be related to your CAI install. If it is the same you know it is a stock issue. The air boxes on some of these sometimes are sensitive to airflow issues to the MAF, I have seen lots of V's without issues with all sorts of different air intake setups though, so it shouldn't be.
Here is a list from the FSM of things to check for an unstable or incorrect idle.
Hope this Helps.
In response to what the issue is I posted an earlier thread explaining everything but the issue is the rpms returning to idle position but dropping to low. Example I started the car this morning it was a little cooler and engine was cold so it idled slightly higher about 1000-1100 rpms. Everything there seems normal, the problem is when I shift into reverse and let out the clutch to start backing out of the driveway(rpms get up to about 3,000) when I engage the clutch to shift into first and the idle control motor takes over the rpms drop down but rather than stopping at idle(750-850rpms) the rpms will drop down to low to 400-500 rpms which causes the engine to bogg down some and then the computer sees the rpms dropping to low and compensates to kick them back up to idle range. Kicker is this does not happen everytime but it does happen when the engine is hot or cold. History behind how this started was my battery died I had the battery replaced and cleaned the throttle body of built up carbons i.e. I have done this before, used proper cleaning solution and cloths. After battery was hooked back up this is when I noticed vehicle having these symptoms, brought it to dealership and they checked and cleaned up the throttle body again and checked for air leaks everything seemed to be fine. They said they did an idle relearn procedure and that it did not seem to act up anymore for them. Of course the car doesnt seem to act up while the dealership has it. The other day I was trying to isolate the problem and while the car was acting up I stopped applied the parking brake and engaged clutch -shifted in neutral and held clutch in-revved the engine up to about 5000 rpms and watched the rpms fall back down and it duplicated the problem when the rpms fell back down instead of stopping at idol range, they would dropp all the way to 400rpms causing the engine to bogg down. I did this 4 or 5 times and it did the same thing each time. Then I kept the car in neutral but let the clutch out and revved up the rpms again to about 5000rpms and it didnt drop down as low when returning to idle(stopped about 700rpms). I know the issue doesnt have anything to do with the intake because I have had the intake for the past two years and did not have this problem. I had the engine mounts checked and they are fine and checked the intake setup for leaks. At this point I almost think the ecm needs to be reprogramed or something is wrong with the idle control motor that isnt kicking a code. It is weird that the driveability of the car seems to be normal no rough acceleration or deceleration but the issue is when the car is returning to idle. Thanks again for the help:banghead:
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700-850 rpm, wow thats high by my standards...
All my engines rev at about 500rpm in idle. I have a friend with a SC on his car ant it ticks over at 750rpm...
I have to admit there is something up, i only wish i was there to take a look, if you allowed me..Btw try swappin throttlebodies. Isolate the issue to one variable. You know the engine is fine, and the intake kit has proven not to be at fault.
All my engines rev at about 500rpm in idle. I have a friend with a SC on his car ant it ticks over at 750rpm...
I have to admit there is something up, i only wish i was there to take a look, if you allowed me..Btw try swappin throttlebodies. Isolate the issue to one variable. You know the engine is fine, and the intake kit has proven not to be at fault.
Thanks for the detailed explanation. I can't say it brings me closer to being able to help you though.
This engine idles pretty low, it isn't like an older carb engine that you set at 650 or 700.
I have seen these things idle in the 500 range easy, doing manual tests with a scan tool I have gotten some engines to idle as low as 350 rpm.
If the engine is not stalling I would try not to concentrate on this issue or it will just keep bugging you.
I don't want to say nothing is wrong but it almost sounds like your perception that something is wrong is convincing you that the car is broken when it MIGHT not be.
Swapping parts is good if you have them.
When you cleaned the throttle body did you remove it, or just clean it.
As mentioned, vacuum leaks would probably make the car idle higher, not lower.
Also do you still have the factory air box as I suggested?
This engine idles pretty low, it isn't like an older carb engine that you set at 650 or 700.
I have seen these things idle in the 500 range easy, doing manual tests with a scan tool I have gotten some engines to idle as low as 350 rpm.
If the engine is not stalling I would try not to concentrate on this issue or it will just keep bugging you.
I don't want to say nothing is wrong but it almost sounds like your perception that something is wrong is convincing you that the car is broken when it MIGHT not be.
Swapping parts is good if you have them.
When you cleaned the throttle body did you remove it, or just clean it.
As mentioned, vacuum leaks would probably make the car idle higher, not lower.
Also do you still have the factory air box as I suggested?
My feedback:
#1: I'll be honest. I didn;t read all of your post, becuase it was just to hard. Please use some sentance & spacing structure in your posts. Reading what you wrote gave me a headache. More people will read and reply if it doesn't kill them to read your posts. The 'ENTER' ley is your friend. I'm not trying to be an @$$, rather trying to help get more eyes on the problem.
#2: I had a very similar issue, that the idle would shoot up (up to 3000k rpm's sometimes), when I depressed the clutch (like when stopping for a stoplight), and would take about 20 seconds to settle back down. I did the throttle relearn proceedure from the FAQ (the one Tony posted). It fixed the problem. This was after I installed by ported throttle body.
#3: Do the relearn yourself. Your dealership may not have done it for you. It takes less than a minute, and you can definitively cross it off your list, it it doesn't fix the issue. This wouldn't be the first time that a dealer said one thing, and did another.
Good luck,
-Chris
I had a vacuum problem which manifested itself by popping a check engine code.
We did a "smoke test", in which a small smoke generator wand is passed over the running motor. Any vacuum draws in the smoke.
What we found was a little vacuum port at the rear of the manifold was leaking. This port has a dummy fitting on it, which I believe was used in older Cameros. Cadillac just puts a rubber cover on this little port, which cover can dislodge. You cannot "see" this port except through a small mirror. Good luck.
We did a "smoke test", in which a small smoke generator wand is passed over the running motor. Any vacuum draws in the smoke.
What we found was a little vacuum port at the rear of the manifold was leaking. This port has a dummy fitting on it, which I believe was used in older Cameros. Cadillac just puts a rubber cover on this little port, which cover can dislodge. You cannot "see" this port except through a small mirror. Good luck.
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Any luck findin the issue?
You know, just a thought...The idle air hole could have some obstruction causin this issue. Your MAF sensor could also be dirty, so at low air flow it doesnt properly read the air flow. Your manifold could be gunked up with oil, and your MAP sensor is not reading low pressure situations...
Its a simple problem that is being missed. Or a combination of small problems...Give them all a nice clean up and have the MAP and MAF checked out...
You know, just a thought...The idle air hole could have some obstruction causin this issue. Your MAF sensor could also be dirty, so at low air flow it doesnt properly read the air flow. Your manifold could be gunked up with oil, and your MAP sensor is not reading low pressure situations...
Its a simple problem that is being missed. Or a combination of small problems...Give them all a nice clean up and have the MAP and MAF checked out...
There's your problem.
Double and triple check your intake tract for leaks. You had to disconnect everything to get at the TB, so I suspect you may have a small air leak. If that doesn't work, try a throttle relearn:
(from the FAQ- Thanks Reed! :thumbsup
# Turn car off, wait a few seconds.
# Hold throttle to the floor and keep it there while trying to start the car. It won't start (try only once).
# Turn off ignition.
# Wait about 15 seconds.
# Start car.
If you used anything abrasive on the throttle body it can also cause extra airflow at idle by opening up the area around the throttle plate, but I doubt you did that.
It works on my car and I had almost the same idle problem but I didnt get no codes, I cleaned my tb, bought some maf spray cleaner and cleaned that and all the linkage.:worship::worship::worship:
I am having the exact same issue with my V, so I am just wondering if you ever found a solution? Thanks for the help.
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Another thought, Since the tb has been removed there could be a leak of air in the system...Either from the tb where it connects to the manifold, or through the oil vapor hoses. I have found GM wasnt very smart in this design. One hose on my Tahoe leads to a dead end. And the other is suction. I deleted the deadend one and connected it to the suction line as well.. Beleive it or not milage went up...
FYI you will notice i refer to milage quite a bit, there is a reason, milage is a good reference for engine efficency. The higher the milage the better the efficency and power delivery.
FYI you will notice i refer to milage quite a bit, there is a reason, milage is a good reference for engine efficency. The higher the milage the better the efficency and power delivery.
I had this issue again after having my FAST 90/90 installed a few months ago.
It turned out to be a dryrotted/cracked PCV host connecting the valley cover to the intake manifold (the tube that look slike a U, and is about 3 inches long). It is just press on, not using any host clamps.
I had a leak one other time, and it was the hose connecting the back of the intake to the brake booster.
Like what everyone else has said, the #1 culprit in cases like this is an air leak.
Call around and find a local shop that has a smoke machine like Rey sugested. Those things are amazing. If you have a leak , that will find it quick. There are LOT of places where you can develop a leak post MAF. If you don;t have a leak, then you should consider taking to a *GOOD* Caddy dealer (cough~~LINDSAY~~cough).
-Chris
It turned out to be a dryrotted/cracked PCV host connecting the valley cover to the intake manifold (the tube that look slike a U, and is about 3 inches long). It is just press on, not using any host clamps.
I had a leak one other time, and it was the hose connecting the back of the intake to the brake booster.
Like what everyone else has said, the #1 culprit in cases like this is an air leak.
Call around and find a local shop that has a smoke machine like Rey sugested. Those things are amazing. If you have a leak , that will find it quick. There are LOT of places where you can develop a leak post MAF. If you don;t have a leak, then you should consider taking to a *GOOD* Caddy dealer (cough~~LINDSAY~~cough).
-Chris
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